1. Field of the Invention
This invention relates to carrier-supported catalysts on a transition metal basis for the removal of nitrogen oxides, carbon monoxide and/or organic compounds from exhaust gases, processes for their manufacture, and their use in the treatment of exhaust gases containing nitrogen oxides, carbon monoxide and/or organic compounds.
2. Background Information
It is known that a catalyst can be formed from industrial metal phthalocyanines and a carrier to remove nitrogen oxides, carbon monoxide and/or residual hydrocarbons from exhaust gases (German Laid Open Patent Application No. 35 22 637 and European Laid Open Patent Application No. 0 228 398). For this purpose, the metal phthalocyanines are treated with oxidizing gas mixtures, so that in a controlled partial decomposition of the stable complexes, assisted by the wide separation of the metal ions from one another, as a result of the structure of the complex, a highly irregular, stable and highly-active catalyst preparation is formed which differs greatly from the stoichiometric oxide and from the stoichiometric metal complex.
Several processes are disclosed for the prior fixing of the metal phthalocyanine on carriers which precedes the transformation into the active components. These include the saturation of the carrier with solutions and suspensions, the precipitation of carrier materials from metal phthalocyanine suspensions, with subsequent shaping and drying, the conversion of metal phthalocyanines into soluble derivates, to facilitate saturation, and the direct synthesis of the metal phthalocyanine from soluble preliminary stages on the carriers. If the metal phthalocyanines are to be deposited on an intermediate layer and not applied directly on the carrier, this intermediate layer can be applied not only before the application of the metal phthalocyanines, but also simultaneously with the application of the metal phthalocyanines in a single step.